Fighting spam via greylisting
dj at linuxfromscratch.org
Fri Apr 13 19:19:54 PDT 2007
Jeremy Huntwork wrote:
> TheOldFellow wrote:
>> Did you see this system for 'autowhitelisting' that works with postgrey?
> I looked at this. Postgrey already does autowhitelisting internally. I'm
> not sure which is more effective.
Auto whitelist on greylist? Auto permanent whitelist would be bad, I'm
assuming this is just a retention policy? It should only be for a short
amount of time, a couple hours maybe, however, I believe the expiration
used to be based on the first message time, not the last. If that is
still true, then it should be bugged as it should be configurable.
Also, as to expected delays should postgrey get turned back on. It's
probably been about 18mos since I started using postgrey, and I was
forced to drop postfix about 6 mos back. Anyway, I'm not positive which
ones, I think it was AOL and MSN, but 2 big names were taking an
identical and abnormally long delivery time. They were taking 18
minutes for delivery with the default 5 minute delay in postgrey.
They'd resend 3 times at 1 minute intervals, and then wait another 15
minutes. Unfortunately, I no longer have a linux mailserver where I can
review real mail logs to verify if this is still true. Oh, I never
bothered to 'fix' it either, if they couldn't wait 18 minutes, then they
should have picked up the phone!
-- DJ Lucas
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